As solid state light sources have increased in efficiency and decreased in cost, they are more commonly being used in products as general illumination sources. One way of generating white light and/or substantially white light from solid state light sources is to use a yellow phosphor, whether directly on a chip or remote, to convert blue light from the solid state light sources to a substantially white light. An alternative technique is known as color mixing. In color mixing, light emitted from solid state light sources of two colors (e.g., greenish-white (“mint”) and amber (“red”)) or three colors (e.g., red, green, and blue) is mixed together to create white light and/or substantially white light. In such color mixing applications, it is generally desirable to sense the light being output and to adjust it as the solid state light sources change over time, to maintain a similar and/or near similar color of light.